Laxatives are frequently taken especially by older persons, who have multiple diseases and are disabled. Major differences exist among countries in the type of laxatives taken, and knowledge of the intake patterns is important because of the potential adverse effects associated with particular ingredients. Laxatives and factors related to their use are described in a sample of 3257 patients admitted to 58 hospitals of the Gruppo Italiano di Farmacovigilanza nell'Anziano (GIFA) in 1991. The mean age was 68.2 years, median 73 years, more than 30% were age > or = 80 years, and 48.7% were men. The overall prevalence rates of laxative use during hospital stay and prior to admission were 11.5% and 11.3%, respectively. Increasing age was independently associated with laxative use after adjusting for gender, activities of daily living, cognitive function, number of active medical problems, medications taken, Italian region and length of stay. After excluding the prescriptions for hyperammoniemia, lactulose was the most frequently taken laxative (prevalence: 6.7% during hospital stay and 4.3% prior to hospital admission), followed by anthranoid laxatives such as senna, cascara, rhein and aloe (1.9% in-hospital and 3.3% pre-hospital). Other less frequently taken laxatives were picosulfate, phenolphthalein, lactitol, glycerol, bisacodyl and docusate. These patterns differ substantially from those reported by surveys conducted in other countries. Further studies are needed to assess the risks and benefits related to the intake of specific laxative ingredients.